Calculation of stress intensity factors of thermally loaded cracks using the finite element method

Abstract

The knowledge of stress intensity factors of cracks under conditions of thermal shock loading is very important for the assessment of the integrity of nuclear power plants. Under certain thermal loading conditions, the transient temperature distribution in a component is influenced by the existence of cracks, and thermal singularities may occur at the crack tip. These facts are usually not considered in thermal shock analysis. In this paper stress intensity factors for such load cases are determined by use of the Finite Element (FE) Method. By comparison with analytical results for steady state problems, it is shown that methods for the evaluation of stress intensity factors which are available in nearly every FE code can be successfully applied to problems with thermal singularities. Cracks in plates and in a hollow cylinder subjected to transient thermal loading are discussed. The results are compared with those available from existing FE studies.